Pixel structure of display panel

ABSTRACT

A pixel structure of display panel includes a first substrate, a second substrate, a liquid crystal layer, a first pixel electrode, an insulation layer, a second pixel electrode and a common electrode. The first substrate has a plurality of alignment regions. The second substrate and the first substrate are disposed opposite to each other. The first pixel electrode is a patterned electrode, which includes a plurality of branch electrodes disposed in the alignment regions. The insulation layer is disposed between the first pixel electrode and the liquid crystal layer. The second pixel electrode is a patterned electrode disposed in at least one boundary of each of the alignment regions. The common electrode is disposed on the second substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pixel structure of display panel, andmore particularly, to a pixel structure of display panel with hightransmittance.

2. Description of the Prior Art

Due to its advantages such as compact size and energy efficiency, liquidcrystal display (LCD) panel has been widely used in various types ofelectronic products such as smart phone, notebook computer, tablet PCand TV. The LCD panel includes a first substrate e.g. an arraysubstrate, a second substrate e.g. a counter substrate, and a liquidcrystal layer interposed between the first substrate and the secondsubstrate. In addition, a pixel electrode is disposed on the firstsubstrate and a common electrode is disposed on the second substrate.Under the electric field formed by the voltage difference of the pixelelectrode and the common electrode, the liquid crystal molecules can bedriven to provide display function. As large size LCD panel has beendeveloped rapidly, LCD panel is provided with wide viewing anglecharacteristic so as to satisfy the users' requirements. To achieve wideviewing angle function, a plurality of alignment regions are formed ineach pixel and the pixel electrode includes a plurality of branchelectrodes extended toward different directions such that the liquidcrystal molecules in different alignment regions would tilt towarddifferent directions when driven. During displaying, especially duringdisplaying high grayscale images, however, the fringe field of thebranch electrodes may be distorted due to the excessive fringe fieldeffect, which causes the irregular tilted directions of the liquidcrystal molecules. As a result, dark lines would appear when displayingimages and the efficiency of liquid crystal is reduced. Thetransmittance is accordingly decreased and therefore the display qualityis affected.

SUMMARY OF THE INVENTION

It is therefore one of the objectives of the present invention toprovide a pixel structure of display panel to increase the transmittanceand avoid the generation of dark lines.

In an embodiment of the present invention, a pixel structure of displaypanel is provided. The pixel structure of display panel includes a firstsubstrate, a second substrate, a liquid crystal layer, a first pixelelectrode, an insulation layer, a second pixel electrode and a commonelectrode. The first substrate has a plurality of alignment regions andthe alignment regions include a first alignment region, a secondalignment region, a third alignment region and a fourth alignmentregion. The second substrate is disposed opposite to the firstsubstrate. The liquid crystal layer includes a plurality of liquidcrystal molecules, wherein the liquid crystal molecules are disposedbetween the first substrate and the second substrate, and the liquidcrystal molecules located at the first alignment region, the secondalignment region, the third alignment region and the fourth alignmentregion have different alignment directions. The first pixel electrode isdisposed on the first substrate, wherein the first pixel electrode is apatterned electrode and the first pixel electrode includes a pluralityof first branch electrodes disposed in the first alignment region, aplurality of second branch electrodes disposed in the second alignmentregion, a plurality of third branch electrodes disposed in the thirdalignment region, and a plurality of fourth branch electrodes disposedin the fourth alignment region. At least a portion of the first branchelectrodes are substantially arranged along a first direction, at leasta portion of the second branch electrodes are substantially arrangedalong a second direction, at least a portion of the third branchelectrodes are substantially arranged along a third direction and atleast a portion of the fourth branch electrodes are substantiallyarranged along a fourth direction, wherein the first direction, thesecond direction, the third direction and the fourth direction aredifferent to one another. The first branch electrodes, the second branchelectrodes, the third branch electrodes and the fourth branch electrodesare electrically connected to one another. The insulation layer isdisposed on the first substrate and covers the first pixel electrode.The second pixel electrode is disposed on the insulation layer, whereinthe second pixel electrode is a patterned electrode and the second pixelelectrode is disposed in at least one boundary of each of the alignmentregions. The common electrode is disposed on the second substrate.

In another embodiment of the present invention, a pixel structure ofdisplay panel is provided. The pixel structure of display panel includesa first substrate, a second substrate, a liquid crystal layer, a firstpixel electrode, a patterned insulation layer and a common electrode.The first substrate has a plurality of alignment regions and thealignment regions includes a first alignment region, a second alignmentregion, a third alignment region and a fourth alignment region. Thesecond substrate is disposed opposite to the first substrate. The liquidcrystal layer includes a plurality of liquid crystal molecules, whereinthe liquid crystal molecules are disposed between the first substrateand the second substrate, and the liquid crystal molecules located atthe first alignment region, the second alignment region, the thirdalignment region and the fourth alignment region have differentalignment directions. The first pixel electrode is disposed on the firstsubstrate, wherein the first pixel electrode is a full-surfacedelectrode and is disposed in the first alignment region, the secondalignment region, the third alignment region and the fourth alignmentregion. The patterned insulation layer is disposed on the firstsubstrate and covers the first pixel electrode. The patterned insulationlayer includes a plurality of first insulation branch patterns disposedin the first alignment region, a plurality of second insulation branchpatterns disposed in the second alignment region, a plurality of thirdinsulation branch patterns disposed in the third alignment region and aplurality of fourth insulation branch patterns disposed in the fourthalignment region. At least a portion of the first insulation branchpatterns substantially extends along a first direction, at least aportion of the second insulation branch patterns substantially extendsalong a second direction, at least a portion of the third insulationbranch patterns substantially extends along a third direction and atleast a portion of the fourth insulation branch patterns substantiallyextends along a fourth direction, wherein the first direction, thesecond direction, the third direction and the fourth direction aredifferent to one another. The common electrode is disposed on the secondsubstrate.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a first embodiment ofthe present invention.

FIG. 2 is a top view schematically illustrating an insulation layer ofthe pixel structure of display panel according to the first embodimentof the present invention.

FIG. 3 is a top view schematically illustrating a second pixel electrodeof the pixel structure of display panel according to the firstembodiment of the present invention.

FIG. 4 is a top view schematically illustrating the pixel structure ofdisplay panel when not driven by an electric field according to thefirst embodiment of the present invention.

FIG. 5 is a cross-sectional view of the pixel structure of display paneltaken along line A-A′ of FIG. 4.

FIG. 6 is a top view schematically illustrating the pixel structure ofdisplay panel when driven by the electric field according to the firstembodiment of the present invention.

FIG. 7 is a cross-sectional view of the pixel structure of display paneltaken along line A-A′ of FIG. 6.

FIG. 8 is a schematic diagram illustrating a pixel structure of displaypanel according to a first configuration of the first embodiment of thepresent invention.

FIG. 9 is a schematic diagram illustrating a pixel structure of displaypanel according to a second configuration of the first embodiment of thepresent invention.

FIG. 10 is a diagram illustrating the distribution of transmittance ofthe pixel structure of display panel according to the present embodimentand a comparative embodiment.

FIG. 11 is a diagram illustrating the relation between the transmittanceand a driving voltage of the pixel structure of display panel accordingto the present embodiment and a comparative embodiment.

FIG. 12 is a top view schematically illustrating the pixel structure ofdisplay panel according to an alternative embodiment of the firstembodiment of the present invention.

FIG. 13 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a second embodimentof the present invention.

FIG. 14 is a top view schematically illustrating the pixel structure ofdisplay panel according to the second embodiment of the presentinvention.

FIG. 15 is a cross-sectional view of the pixel structure of displaypanel taken along line B-B′ of FIG. 14.

FIG. 16 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a third embodiment ofthe present invention.

FIG. 17 is a top view schematically illustrating the pixel structure ofdisplay panel according to the third embodiment of the presentinvention.

FIG. 18 is a cross-sectional view of the pixel structure of displaypanel taken along line C-C′ of FIG. 17.

FIG. 19 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a fourth embodimentof the present invention.

FIG. 20 is a top view schematically illustrating the pixel structure ofdisplay panel according to the fourth embodiment of the presentinvention.

FIG. 21 is a cross-sectional view of the pixel structure of displaypanel taken along line D-D′ of FIG. 20.

FIG. 22 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a fifth embodiment ofthe present invention.

FIG. 23 is a top view schematically illustrating the pixel structure ofdisplay panel according to the fifth embodiment of the presentinvention.

FIG. 24 is a cross-sectional view of the pixel structure of displaypanel taken along line F-F′ of FIG. 23.

FIG. 25 is a top view schematically illustrating the pixel structure ofdisplay panel according to an alternative embodiment of the fifthembodiment of the present invention.

FIG. 26 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a sixth embodiment ofthe present invention.

FIG. 27 is a top view schematically illustrating the pixel structure ofdisplay panel according to the sixth embodiment of the presentinvention.

FIG. 28 is a top view schematically illustrating the pixel structure ofdisplay panel according to an alternative embodiment of the sixthembodiment of the present invention.

FIG. 29 is a top view schematically illustrating a first pixel electrodeof a pixel structure of display panel according to a seventh embodimentof the present invention.

FIG. 30 is a top view schematically illustrating a patterned insulationlayer of the pixel structure of display panel according to the seventhembodiment of the present invention.

FIG. 31 is a top view schematically illustrating a second pixelelectrode of the pixel structure of display panel according to theseventh embodiment of the present invention.

FIG. 32 is a top view schematically illustrating the pixel structure ofdisplay panel according to the seventh embodiment of the presentinvention.

FIG. 33 is a cross-sectional view of the pixel structure of displaypanel taken along line E-E′ of FIG. 32.

FIG. 34 is a top view schematically illustrating a pixel structure ofdisplay panel according to an eighth embodiment of the presentinvention.

FIG. 35 is a cross-sectional view of the pixel structure of displaypanel taken along line G-G′ of FIG. 34.

DETAILED DESCRIPTION

To provide a better understanding of the present invention to theskilled users in the technology of the present invention, preferredembodiments will be detailed as follows. The preferred embodiments ofthe present invention are illustrated in the accompanying drawings withnumbered elements to elaborate the contents and effects to be achieved.

Please refer to FIGS. 1-5. FIG. 1 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a first embodiment of the present invention, FIG. 2is a top view schematically illustrating an insulation layer of thepixel structure of display panel according to the first embodiment ofthe present invention, FIG. 3 is a top view schematically illustrating asecond pixel electrode of the pixel structure of display panel accordingto the first embodiment of the present invention, FIG. 4 is a top viewschematically illustrating the pixel structure of display panel when notdriven by an electric field according to the first embodiment of thepresent invention, and FIG. 5 is a cross-sectional view of the pixelstructure of display panel taken along line A-A′ of FIG. 4, wherein onlya first substrate and layers disposed thereon are illustrated in FIG. 4,and a second substrate and layers disposed thereon, a liquid crystallayer and other components are not illustrated in FIG. 4 forhighlighting the features of the pixel structure of display. As shown inFIGS. 4-5, the pixel structure 1 of display panel includes a firstsubstrate 10, a second substrate 20, a liquid crystal layer 30, a firstpixel electrode 12, an insulation layer 14, a second pixel electrode 16and a common electrode 22. The first substrate 10 has a plurality ofalignment regions. For example, the alignment regions of the presentembodiment include a first alignment region 101, a second alignmentregion 102, a third alignment region 103 and a fourth alignment region104, but not limited thereto. For instance, the number of alignmentregions may be modified. In addition, the shape and the size of thefirst alignment region 101, the second alignment region 102, the thirdalignment region 103 and the fourth alignment region 104 of the presentembodiment are substantially the same, but not limited thereto. Forexample, the alignment regions may have different sizes or differentshapes. The second substrate 20 is disposed opposite to the firstsubstrate 10. The first substrate 10 and the second substrate 20 mayrespectively be a transparent substrate e.g. a glass substrate, a quartzsubstrate, a plastic substrate or another suitable rigid or flexiblesubstrate. In the present embodiment, the first substrate 10 is an arraysubstrate (or known as a thin-film transistor substrate), and switchingunits such as thin-film transistor units, conducting lines e.g. gatelines, data lines and common lines, color filters, storage capacitors,or other essential units may be disposed on the first substrate 10. Thepositions and the functions of the above mentioned units are known tothe skilled person in the art and will not be redundantly described. Inaddition, the second substrate 20 is a counter substrate.Light-shielding patterns such as a black matrix, a color filter or otheressential units may be disposed on the second substrate 20. Thepositions and the functions of the above mentioned units are known tothe skilled person in the art and will not be redundantly described. Theliquid crystal layer 30 includes a plurality of liquid crystal moleculesLC, wherein the liquid crystal molecules LC are disposed between thefirst substrate 10 and the second substrate 20, and the liquid crystalmolecules LC located at the first alignment region 101, the secondalignment region 102, the third alignment region 103 and the fourthalignment region 104 have different alignment directions. The liquidcrystal molecules LC may be vertical alignment (VA) liquid crystalmolecules and may be negative typed liquid crystal molecules, but notlimited thereto. As shown in FIG. 1, FIG. 4 and FIG. 5, the first pixelelectrode 12 is disposed on the first substrate 10. The first pixelelectrode 12 of the present embodiment is a transparent electrode andmay be made of transparent conductive materials such as indium tin oxide(ITO), indium zinc oxide (IZO), or other suitable transparent conductivematerials, but not limited thereto. In other alternative embodiments ofthe present invention, the first pixel electrode 12 may be anon-transparent electrode and may be made of non-transparent conductivematerials such as metal. In addition, the first pixel electrode 12 maybe a single-layered structure or a stacked multi-layered structure. Thefirst pixel electrode 12 is a patterned electrode and the first pixelelectrode 12 includes a plurality of first branch electrodes 121disposed in the first alignment region 101, a plurality of second branchelectrodes 122 disposed in the second alignment region 102, a pluralityof third branch electrodes 123 disposed in the third alignment region103, and a plurality of fourth branch electrodes 124 disposed in thefourth alignment region 104, wherein the first branch electrodes 121,the second branch electrodes 122, the third branch electrodes 123 andthe fourth branch electrodes 124 are electrically connected to oneanother. Furthermore, at least a portion of the first branch electrodes121 are substantially arranged along a first direction D1, at least aportion of the second branch electrodes 122 are substantially arrangedalong a second direction D2, at least a portion of the third branchelectrodes 123 are substantially arranged along a third direction D3 andat least a portion of the fourth branch electrodes 124 are substantiallyarranged along a fourth direction D4, wherein the first direction D1,the second direction D2, the third direction D3 and the fourth directionD4 are different to one another. Additionally, there are slits 12Sbetween any two adjacent (adjoining) branch electrodes. The insulationlayer 14 is disposed on the first substrate 10 and covers the firstpixel electrode 12. As shown in FIG. 2 and FIG. 4, the insulation layer14 of the present embodiment is a full-surfaced insulation layer. Inother words, the insulation layer 14 substantially completely covers thefirst alignment region 101, the second alignment region 102, the thirdalignment region 103, the fourth alignment region 104 and the firstpixel electrode 12, but not limited thereto. As shown in FIGS. 3-5, thesecond pixel electrode 16 is disposed on the insulation layer 14,wherein the second pixel electrode 16 is a patterned electrode and thesecond pixel electrode 16 is disposed in at least one boundary of eachof the alignment regions. More specifically, the second pixel electrode16 is disposed in the common boundary of any two adjoining alignmentregions of the alignment regions. In other words, the second pixelelectrode 16 is disposed between the first alignment region 101 and thesecond alignment region 102, the second alignment region 102 and thethird alignment region 103, the third alignment region 103 and thefourth alignment region 104, and the fourth alignment region 104 and thefirst alignment region 101. The second pixel electrode 16 of the presentembodiment is a transparent electrode and may be made of transparentconductive materials such as indium tin oxide (ITO), indium zinc oxide(IZO), or other suitable transparent conductive materials, but notlimited thereto. In other alternative embodiments of the presentinvention, the second pixel electrode 16 may be a non-transparentelectrode and may be made of non-transparent conductive materials suchas metal. In addition, the second pixel electrode 16 may be asingle-layered structure or a stacked multi-layered structure. Thecommon electrode 22 is disposed on the second substrate 20. The commonelectrode 22 of the present embodiment is a transparent electrode andmay be made of transparent conductive materials such as indium tin oxide(ITO), indium zinc oxide (IZO), or other suitable transparent conductivematerials, but not limited thereto. In addition, the common electrode 22of the present embodiment is a full-surfaced electrode, in other words,the common electrode 22 substantially completely covers the firstalignment region 101, the second alignment region 102, the thirdalignment region 103 and the fourth alignment region 104 without anyslits or openings, but not limited thereto. As shown in FIG. 5, thepixel structure 1 of display panel further includes a first alignmentfilm 18 and a second alignment film 24. The first alignment film 18 isdisposed on the first substrate 10 and covers the insulation layer 14and the second pixel electrode 16. The second alignment film 24 isdisposed on the second substrate 20 and covers the common electrode 22.In other words, the first alignment film 18 and the second alignmentfilm 24 are disposed on two opposite sides of the liquid crystal layer30 for aligning the liquid crystal molecules LC. In the presentembodiment, the first alignment film 18 and the second alignment film 24may be made through polymer stabilized alignment (PSA) technique, butnot limited thereto. For instance, the first alignment film 18 mayinclude a first polymer auxiliary alignment layer and the secondalignment film 24 may include a second polymer auxiliary alignmentlayer, but not limited thereto.

In the present embodiment, the first pixel electrode 12 further includesa main part 12M. The main part 12M of the first pixel electrode 12 isdisposed in a common boundary of any two adjoining alignment regions ofthe alignment regions, in other words, the main part 12M of the firstpixel electrode 12 is disposed in a common boundary of any two adjacentalignment regions. In other words, the main part 12M is disposed betweenthe first alignment region 101 and the second alignment region 102, thesecond alignment region 102 and the third alignment region 103, thethird alignment region 103 and the fourth alignment region 104, and thefourth alignment region 104 and the first alignment region 101. Inaddition, the main part 12M of the first pixel electrode 12 isrespectively connected to a first end 121A of each of the first branchelectrodes 121, a first end 122A of each of the second branch electrodes122, a first end 123A of each of the third branch electrodes 123 and afirst end 124A of each of the fourth branch electrodes 124. The mainpart 12M of the first pixel electrode 12 substantially overlaps thesecond pixel electrode 16 in a vertical projection direction Z. Forinstance, the main part 12M of the first pixel electrode 12 and thesecond pixel electrode 16 substantially respectively include a cruciform(cross-shaped) electrode and the width of the main part 12M of the firstpixel electrode 12 is larger than the width of the second pixelelectrode 16, but not limited thereto. When viewed from the direction ofthe vertical projection direction Z, the main part 12M of the firstpixel electrode 12 divides the first substrate 10 into four quadrants.The first alignment region 101, the second alignment region 102, thethird alignment region 103 and the fourth alignment region 104 arerespectively disposed in the first quadrant, the second quadrant, thethird quadrant and the fourth quadrant. In the present embodiment, thefirst branch electrodes 121 are substantially arranged and extendedalong the first direction D1, the second branch electrodes 122 aresubstantially arranged and extended along the second direction D2, thethird branch electrodes 123 are substantially arranged and extendedalong the third direction D3, and the fourth branch electrodes 124 aresubstantially arranged and extended along the fourth direction D4. Inaddition, the first direction D1 is substantially perpendicular to thesecond direction D2, the second direction D2 is substantiallyperpendicular to the third direction D3, the third direction D3 issubstantially perpendicular to the fourth direction D4 and the fourthdirection D4 is substantially perpendicular to the first direction D1.For example, if the azimuth angle in the horizontal direction measuredcounterclockwise from a referent direction, as from the right direction,in FIG. 1 is defined as 0 degree and the counterclockwise direction isdefined as forward direction, then the first direction D1 issubstantially 45 degrees, the second direction D2 is substantially 135degrees, the third direction D3 is substantially 225 degrees and thefourth direction D4 is substantially 315 degrees, but not limitedthereto. In an alternative embodiment, the first direction D1, thesecond direction D2, the third direction D3 and the fourth direction D4may not be perpendicular to one another. For instance, the includedangle of the first direction D1 and the fourth direction D4 may be 80degrees and the included angle of the second direction D2 and the thirddirection D3 may be 80 degrees. In addition, the first pixel electrode12 may further include an outer frame part 12P. The outer frame part 12Psurrounds the first alignment region 101, the second alignment region102, the third alignment region 103 and the fourth alignment region 104.The outer frame part 12P is connected to the first branch electrodes121, the second branch electrodes 122, the third branch electrodes 123and the fourth branch electrodes 124. For example, the outer frame part12P is respectively connected to a second end 121B of each of the firstbranch electrodes 121, a second end 122B of each of the second branchelectrodes 122, a second end 123B of each of the third branch electrodes123 and a second end 124B of each of the fourth branch electrodes 124.

The driving method of the pixel structure of display panel of thepresent embodiment is elaborated as follows. As shown in FIGS. 4-5, whennot driven by the electric field, the liquid crystal molecules LClocated at the first alignment region 101, the second alignment region102, the third alignment region 103 and the fourth alignment region 104substantially stand vertically and pre tilt toward the third directionD3, the fourth direction D4, the first direction D1 and the seconddirection D2 respectively, i.e. the liquid crystal molecules LC pre tilttoward the intersection part of the main part 12M of the first pixelelectrode 12. Please refer to FIGS. 6-7. FIG. 6 is a top viewschematically illustrating the pixel structure of display panel whendriven by an electric field according to the first embodiment of thepresent invention. FIG. 7 is a cross-sectional view of the pixelstructure of display panel taken along line A-A′ of FIG. 6. As shown inFIGS. 6-7, in the present embodiment, the first pixel electrode 12 iselectrically connected to the drain electrode of the switching unit (notshown in the figure) so as to have a first driving voltage (e.g. pixelvoltage), and the common electrode 22 is electrically connected to thecommon line (not shown in the figure) so as to have a common voltage. Inaddition, the second pixel electrode 16 may be electrically connected tothe first pixel electrode 12 and also have the first driving voltage(e.g. pixel voltage). When the liquid crystal molecules LC are driven bythe electric field between the first pixel electrode 12 and the commonelectrode 22 and the electric field between the second pixel electrode16 and the common electrode 22, the liquid crystal molecules LC locatedat the first alignment region 101, the second alignment region 102, thethird alignment region 103 and the fourth alignment region 104 wouldtilt and have different alignment direction. For instance, the liquidcrystal molecules LC located at the first alignment region 101, thesecond alignment region 102, the third alignment region 103 and thefourth alignment region 104 would respectively tilt toward the thirddirection D3, the fourth direction D4, the first direction D1 and thesecond direction D2 respectively, i.e. the liquid crystal molecules LCtilt toward the intersection part of the main part 12M of the firstpixel electrode 12. Due to the electric field distortions generated bythe excessive fringe field effect of the edges of the main part 12M ofthe first pixel electrode 12 and the edges of the branch electrodes, theinsulation layer 14 disposed between the first pixel electrode 12 andthe liquid crystal layer 30 is able to provide an isolation effect. Theimpact of liquid crystal molecules LC influenced by the fringe field areaccordingly decreased, and therefore the liquid crystal molecules LCcorresponding to the edges of the main part 12M of the first pixelelectrode 12 and the edges of the branch electrodes only experienceslight electric field distortions. As a result, the liquid crystalmolecules LC under high voltage operations would not be deviated fromthe direction of the alignment regions as not being influenced byexcessive electric field distortions and the transmittance is thereforeimproved. Furthermore, small and regular variations of equipotentialsurface may be provided by the second pixel electrode 16, which cansubstitute for the fringe field of the main part 12M of the first pixelelectrode 12 and drive the liquid crystal molecules LC, and thereforemay reduce the width of the dark line of the common boundaries (commonborders) of the alignment regions. The transmittance may be accordinglyimproved. By applying the driving method mentioned above, the irregulararrangement of the liquid crystal molecules LC may be solved and thegeneration of the dark lines is avoided. It is worth noting that, inother alternative embodiments, the second pixel electrode 16 may not beelectrically connected to the first pixel electrodes 12 and may have adifferent driving voltage or the same first driving voltage (e.g. pixelvoltage) as the first pixel electrode 12. For instance, the second pixelelectrode 16 may have a second driving voltage, and the second drivingvoltage is higher than the first driving voltage, but not limitedthereto. In addition, the second driving voltage may be provided with aconstant voltage source, in other words, the second pixel electrode 16of each pixel structure has the same second driving voltage.Alternatively, the second pixel electrodes 16 of each pixel structuremay be controlled by a corresponding switching unit (e.g. thin-filmtransistor unit) such that the second pixel electrode 16 of each pixelstructure has a different second driving voltage.

Please refer to FIG. 8 in view of FIGS. 1-7. FIG. 8 is a schematicdiagram illustrating a pixel structure of display panel according to afirst configuration of the first embodiment of the present invention. Asshown in FIG. 8, the pixel structure 1A of display panel includes afirst switching unit SW1 and a second switching unit SW2, where thefirst pixel electrode 12 is electrically connected to the drainelectrode of the first switching unit SW1 via a first through hole TH1,and the second pixel electrode 16 is electrically connected to the drainelectrode of the second switching unit SW2 via a second through holeTH2. The first through hole TH1 and the second through hole TH2 arelocated outside the active region (effective display region), and thusthe aperture ratio is unaffected. In this configuration, the firstswitching unit SW1 and the second switching unit SW2 share the same gateline GL but connect to a first data line DL1 and a second data line DL2respectively. Specifically, the gate electrodes of the first switchingunit SW1 and the second switching unit SW2 are electrically connected tothe same gate line GL, while the source electrodes of the firstswitching unit SW1 and the second switching unit SW2 are electricallyconnected to the first data line DL1 and the second data line DL2respectively. In addition, the pixel structure 1A of display panel mayfurther include a common line CL, which partially overlaps the firstpixel electrode 12 and the second pixel electrode 16 to form storagecapacitors respectively. By virtue of the above configuration, the firstpixel electrode 12 and the second pixel electrode 16 may be drivenindependently, i.e. the first pixel electrode 12 may be provided with afirst driving voltage and the second pixel electrode 16 may be providedwith a second driving voltage. In alternative configurations, the firstswitching unit SW1 and the second switching unit SW2 may share the samedata line but connect to different gate lines, or the first switchingunit SW1 and the second switching unit SW2 may connect to different gatelines and different data lines.

Please refer to FIG. 9 in view of FIGS. 1-7. FIG. 9 is a schematicdiagram illustrating a pixel structure of display panel according to asecond configuration of the first embodiment of the present invention.As shown in FIG. 9, the pixel structure 1B of display panel includes aswitching unit SW, a gate line GL, a data line DL and a common line CL.The first pixel electrode 12 is electrically connected to the drainelectrode of the switching unit SW via a through hole TH. The drainelectrode of the switching unit SW may extend to the active region andpartially overlap the common line CL. The through hole TH may be locatedin the overlapping region of the drain electrode and the common line CL,and thus the aperture ratio is unaffected. In this configuration, thefirst pixel electrode 12 is provided with a first driving voltage by theswitching unit SW, and the second pixel electrode 16 is electricallyconnected to the first pixel electrode 12, thereby having the firstdriving voltage as well.

Please refer to FIG. 10. FIG. 10 is a diagram illustrating thedistribution of transmittance of the pixel structure of display panelaccording to the present embodiment and a comparative embodiment,wherein only the first pixel electrode is disposed in the pixelstructure of display panel of the comparative embodiment withoutdisposing the insulation layer and the second pixel electrode. Thecurved line A illustrates the transmittance distribution of the pixelstructure of display panel according to the comparative embodiment andthe curved line B illustrates the transmittance distribution of thepixel structure of display panel according to the present embodiment.The X axis represents the distance in the horizontal direction of thepixel structure of display panel (unit: μm (micrometer)) and the Y axisrepresents the transmittance (no unit). As shown in FIG. 10, the curvedline A shows the transmittance distributed in apparent alternating highand low fluctuations, which means the pixel structure of display panelof the comparative embodiment suffered from serious dark line problems.The curved line B shows more smooth and continuous transmittancedistribution, which is a proof of the pixel structure of display panelaccording to the present embodiment addressing the problem of electricfield distortion and effectively eliminating the dark line problems.

Please refer to FIG. 11. FIG. 11 is a diagram illustrating the relationbetween the transmittance and a driving voltage of the pixel structureof display panel according to the present embodiment and a comparativeembodiment, wherein only the first pixel electrode is disposed in thepixel structure of display panel of the comparative embodiment withoutdisposing the insulation layer and the second pixel electrode. Thecurved line C illustrates the relationship diagram of the transmittanceand the driving voltage of the pixel structure of display panelaccording to the comparative embodiment and the curved line Dillustrates the relationship diagram of the transmittance and thedriving voltage of the transmittance of the pixel structure of displaypanel according to the present embodiment. The X axis represents thedriving voltage (unit: V) and the Y axis represents the transmittance.As shown in FIG. 11, when the driving voltage is higher than 6 volts,the transmittance of the curved line D is higher than the transmittanceof the curved line C, which is a proof of the pixel structure of displaypanel according to the present embodiment addressing the problem ofelectric field distortion under high grayscale operations andeffectively increasing the transmittance.

The pixel structure of display panel is not limited by theaforementioned embodiment, and may have other different preferredembodiments. To simplify the description, the identical components ineach of the following embodiments are marked with identical symbols. Formaking it easier to compare the difference between the embodiments, thefollowing description will detail the dissimilarities among differentembodiments and the identical features will not be redundantlydescribed.

Please refer to FIG. 12. FIG. 12 is a top view schematicallyillustrating the pixel structure of display panel according to analternative embodiment of the first embodiment of the present invention.As shown in FIG. 12, the pixel structure 1′ of display panel of thealternative embodiment is similar to the first embodiment except for thepattern of the first pixel electrode 12. Specifically, the first pixelelectrode 12 of this alternative embodiment includes the main part 12M,the branch electrodes e.g. the first branch electrodes 121, the secondbranch electrodes 122, the third branch electrodes 123 and the fourthbranch electrodes 124 and slits 12S between any two adjacent branchelectrodes, but excludes the outer frame part. Without the outer framepart, the pixel structure 1′ of display panel is also able to modify theelectric field distortion, effectively eliminate the dark line problems,and increase the transmittance.

Please refer to FIGS. 13-15. FIG. 13 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a second embodiment of the present invention. FIG. 14is a top view schematically illustrating the pixel structure of displaypanel according to the second embodiment of the present invention. FIG.15 is a cross-sectional view of the pixel structure of display paneltaken along line B-B′ of FIG. 14. As shown in FIGS. 13-15, thedifference between the present embodiment and the first embodiment isthat the first pixel electrode 12 of the pixel structure 2 of displaypanel does not include the main part and each of branch electrodes isconnected to another corresponding branch electrode. More specifically,a first end 121A of a portion of the first branch electrodes 121 isconnected to a first end 122A of a portion of the second branchelectrodes 122, a first end 121A of the other portion of the firstbranch electrodes 121 is connected to a first end 124A of a portion ofthe fourth branch electrodes 124; a first end 122A of a portion of thesecond branch electrodes 122 is connected to a first end 121A of aportion of the first branch electrodes 121, a first end 122A of theother portion of the second branch electrodes 122 is connected to afirst end 123A of a portion of the third branch electrodes 123; a firstend 123A of a portion of the third branch electrodes 123 is connected toa first end 122A of a portion of the second branch electrodes 122, afirst end 123A of the other portion of the third branch electrodes 123is connected to a first end 124A of a portion of the fourth branchelectrodes 124; a first end 124A of a portion of the fourth branchelectrodes 124 is connected to a first end 123A of a portion of thethird branch electrodes 123, and a first end 124A of the other portionof the fourth branch electrodes 124 is connected to a first end 121A ofa portion of the first branch electrodes 121. In addition, the secondpixel electrode 16 substantially includes a cruciform electrode and thesecond pixel electrode 16 substantially overlaps the first ends 121A ofthe first branch electrodes 121, the first ends 122A of the secondbranch electrodes 122, the first ends 123A of the third branchelectrodes 123 and the first ends 124A of the fourth branch electrodes124 in the vertical projection direction Z.

Please refer to FIGS. 16-18. FIG. 16 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a third embodiment of the present invention. FIG. 17is a top view schematically illustrating the pixel structure of displaypanel according to the third embodiment of the present invention. FIG.18 is a cross-sectional view of the pixel structure of display paneltaken along line C-C′ of FIG. 17. As shown in FIGS. 16-18, thedifference between the present embodiment and the embodiments mentionedabove is that the main part 12M of the first pixel electrode 12 of thepixel structure 3 of display panel of the present embodiment is disposedin a portion of the first alignment region 101, a portion of the secondalignment region 102, a portion of the third alignment region 103, aportion of the fourth alignment region 104 and a common boundary of anytwo adjoining (adjacent) alignment regions of the alignment regions. Inaddition, the main part 12M of the first pixel electrode 12 is connectedto a first end 121A of each of the first branch electrodes 121, a firstend 122A of each of the second branch electrodes 122, a first end 123Aof each of the third branch electrodes 123 and a first end 124A of eachof the fourth branch electrodes 124. The main part 12M of the firstpixel electrode 12 substantially overlaps the second pixel electrode 16in the vertical projection direction Z. For example, the main part 12Mof the first pixel electrode 12 substantially includes a quadrangleelectrode (or known as a diamond electrode or a rhombus electrode). Thequadrangle electrode has a first side edge S1, a second side edge S2, athird side edge S3 and a fourth side edge S4. The first side edge S1 isdisposed in the first alignment region 101 and is connected to the firstbranch electrodes 121, the second side edge S2 is disposed in the secondalignment region 102 and is connected to the second branch electrodes122, the third side edge S3 is disposed in the third alignment region103 and is connected to the third branch electrodes 123, the fourth sideedge S4 is disposed in the fourth alignment region 104 and is connectedto the fourth branch electrodes 124, and the second pixel electrode 16substantially includes a cruciform electrode, but not limited thereto.The first side edge S1, the second side edge S2, the third side edge S3and the fourth side edge S4 may be but not limited to be perpendicularto the corresponding first branch electrodes 121, the second branchelectrodes 122, the third branch electrodes 123 and the fourth branchelectrodes 124. In an alternative embodiment, the first side edge S1,the second side edge S2, the third side edge S3 and the fourth side edgeS4 are not perpendicular to the corresponding first branch electrodes121, the second branch electrodes 122, the third branch electrodes 123and the fourth branch electrodes 124, in other words, they may haveincluded angles which not equal to 90 degrees.

Please refer to FIGS. 19-21. FIG. 19 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a fourth embodiment of the present invention. FIG. 20is a top view schematically illustrating the pixel structure of displaypanel according to the fourth embodiment of the present invention. FIG.21 is a cross-sectional view of the pixel structure of display paneltaken along line D-D′ of FIG. 20. As shown in FIGS. 19-21, the formationof the main part 12M of the first pixel electrode 12 and the connectionsbetween the branch electrodes of the pixel structure 4 of display panelof the present embodiment are similar to the third embodiment, thedifference between the present embodiment and the third embodiment isthat the main part 12M of the first pixel electrode 12 further has anopening 12X corresponding to the common boundaries of any two adjacentalignment regions. In other words, the opening 12X is disposed betweenthe first alignment region 101 and the second alignment region 102, thesecond alignment region 102 and the third alignment region 103, thethird alignment region 103 and the fourth alignment region 104, and thefourth alignment region 104 and the first alignment region 101. Inaddition, the opening 12X of the main part 12M of the first pixelelectrode 12 substantially at least partially overlaps the second pixelelectrode 16 in the vertical projection direction Z. For instance, theopening 12X of the main part 12M of the first pixel electrode 12substantially includes a cruciform opening and the second pixelelectrode 16 substantially includes a cruciform electrode. In addition,the width of the opening 12X of the main part 12M of the first pixelelectrode 12 may be slightly larger than the width of the second pixelelectrode 16, but not limited thereto.

Please refer to FIGS. 22-24. FIG. 22 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a fifth embodiment of the present invention. FIG. 23is a top view schematically illustrating the pixel structure of displaypanel according to the fifth embodiment of the present invention. FIG.24 is a cross-sectional view of the pixel structure of display paneltaken along line F-F′ of FIG. 23. As shown in FIGS. 22-24, in the pixelstructure 5 of display panel of the fifth embodiment of the presentinvention, the main part 12M of the first pixel electrode 12 is disposedin the common boundaries of any two adjoining (adjacent) alignmentregions of the alignment regions. In other words, the main part 12M isdisposed between the first alignment region 101 and the second alignmentregion 102, the second alignment region 102 and the third alignmentregion 103, the third alignment region 103 and the fourth alignmentregion 104, and the fourth alignment region 104 and the first alignmentregion 101. In addition, the main part 12M of the first pixel electrode12 is connected to the first end 121A and the second end 121B of aportion of each of the first branch electrodes 121, the first end 122Aand the second end 122B of a portion of each of the second branchelectrodes 122, the first end 123A and the second end 123B of a portionof each of the third branch electrodes 123 and the first end 124A andthe second end 124B of a portion of each of the fourth branch electrodes124. Furthermore, the outer frame part 12P is connected to the first end121A and the second end 121B of the other portion of each of the firstbranch electrodes 121, the first end 122A and the second end 122B of theother portion of each of the second branch electrodes 122, the first end123A and the second end 123B of the other portion of each of the thirdbranch electrodes 123, and the first end 124A and the second end 124B ofthe other portion of each of the fourth branch electrodes 124.Additionally, the second pixel electrode 16 is disposed in an outsideboundary of the first alignment region 101 (e.g. the right side boundaryin the figure), an outside boundary of the second alignment region 102(e.g. the left side boundary in the figure), an outside boundary of thethird alignment region 103 (e.g. the left side boundary in the figure),an outside boundary of the fourth alignment region 104 (e.g. the rightside boundary in the figure), a common boundary of the first alignmentregion 101 and the fourth alignment region 104 and a common boundary ofthe second alignment region 102 and the third alignment region 103. Forinstance, in the present embodiment, the main part 12M of the firstpixel electrode 12 substantially includes a cruciform electrode and thesecond pixel electrode 16 substantially includes an H-shaped electrode,but not limited thereto.

When the liquid crystal molecules LC are driven by the electric fieldbetween the first pixel electrode 12 and the common electrode 22 and theelectric field between the second pixel electrode 16 and the commonelectrode 22, the liquid crystal molecules LC located at the firstalignment region 101, the second alignment region 102, the thirdalignment region 103 and the fourth alignment region 104 would tilt andhave different alignment direction. For instance, the liquid crystalmolecules LC located at the first alignment region 101, the secondalignment region 102, the third alignment region 103 and the fourthalignment region 104 would respectively tilt toward the first directionD1, the second direction D2, the third direction D3 and the fourthdirection D4 respectively. Specifically, the liquid crystal molecules LClocated at the first alignment region 101 and the fourth alignmentregion 104 tilt toward the right side T-junction of the H-shaped secondpixel electrode 16, and the liquid crystal molecules LC located at thesecond alignment region 102 and the third alignment region 103 tilttoward the left side T-junction of the H-shaped second pixel electrode16.

Please refer to FIG. 25. FIG. 25 is a top view schematicallyillustrating the pixel structure of display panel according to analternative embodiment of the fifth embodiment of the present invention.As shown in FIG. 25, the formation of the main part 12M of the firstpixel electrode 12 and the connections between the branch electrodes ofthe pixel structure 5′ of display panel of the present embodiment aresimilar to the fifth embodiment, the difference between the presentembodiment and the fifth embodiment is that the main part 12M of thefirst pixel electrode 12 further has an opening 12X corresponding to thecommon boundaries of any two adjacent alignment regions. In other words,the opening 12X is disposed between the first alignment region 101 andthe second alignment region 102, the second alignment region 102 and thethird alignment region 103, the third alignment region 103 and thefourth alignment region 104, and the fourth alignment region 104 and thefirst alignment region 101. In addition, the opening 12X of the mainpart 12M of the first pixel electrode 12 substantially at leastpartially overlaps the second pixel electrode 16 in the verticalprojection direction Z. For instance, the opening 12X of the main part12M of the first pixel electrode 12 substantially includes a cruciformopening and the second pixel electrode 16 substantially includes anH-shaped electrode. In addition, the width of the opening 12X of themain part 12M of the first pixel electrode 12 may be slightly largerthan the width of the second pixel electrode 16, but not limitedthereto.

Please refer to FIGS. 26-27. FIG. 26 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a sixth embodiment of the present invention. FIG. 27is a top view schematically illustrating the pixel structure of displaypanel according to the sixth embodiment of the present invention. Asshown in FIGS. 26-27, the shape of the first pixel electrode 12 in thepixel structure 6 of display panel of the present embodiment is similarto the shape of the first pixel electrode 12 in the first embodiment andthe arrangement of the main part 12M, the outer frame part 12P and thebranch electrodes will not be redundantly described. The differencebetween the first embodiment and the present embodiment is that thesecond pixel electrode 16 is disposed in two outside boundaries of thefirst alignment region 101 (e.g. the right side boundary and the upperside boundary in the figure), two outside boundaries of the secondalignment region 102 (e.g. the left side boundary and the upper sideboundary in the figure), two outside boundaries of the third alignmentregion 103 (e.g. the left side boundary and the lower side boundary inthe figure) and two outside boundaries of the fourth alignment region104 (e.g. the right side boundary and the lower side boundary in thefigure). More specifically, the second pixel electrode 16 substantiallyincludes a hollow square shaped electrode and surrounds the firstalignment region 101, the second alignment region 102, the thirdalignment region 103 and the fourth alignment region 104.

Please refer to FIG. 28. FIG. 28 is a top view schematicallyillustrating the pixel structure of display panel according to analternative embodiment of the sixth embodiment of the present invention.As shown in FIG. 28, the formation of the main part 12M of the firstpixel electrode 12 and the connections between the branch electrodes ofthe pixel structure 6′ of display panel of the present embodiment aresimilar to the sixth embodiment, the difference between the presentembodiment and the sixth embodiment is that the main part 12M of thefirst pixel electrode 12 further has an opening 12X corresponding to thecommon boundaries of any two adjacent alignment regions. In other words,the opening 12X is disposed between the first alignment region 101 andthe second alignment region 102, the second alignment region 102 and thethird alignment region 103, the third alignment region 103 and thefourth alignment region 104, and the fourth alignment region 104 and thefirst alignment region 101. In addition, the opening 12X of the mainpart 12M of the first pixel electrode 12 substantially partiallyoverlaps the second pixel electrode 16 in the vertical projectiondirection Z. For instance, the opening 12X of the main part 12M of thefirst pixel electrode 12 substantially includes a cruciform opening andthe second pixel electrode 16 substantially includes a hollow squareshaped electrode, but not limited thereto.

Please refer to FIGS. 29-33. FIG. 29 is a top view schematicallyillustrating a first pixel electrode of a pixel structure of displaypanel according to a seventh embodiment of the present invention. FIG.30 is a top view schematically illustrating a patterned insulation layerof the pixel structure of display panel according to the seventhembodiment of the present invention. FIG. 31 is a top view schematicallyillustrating a second pixel electrode of the pixel structure of displaypanel according to the seventh embodiment of the present invention. FIG.32 is a top view schematically illustrating the pixel structure ofdisplay panel according to the seventh embodiment of the presentinvention. FIG. 33 is a cross-sectional view of the pixel structure ofdisplay panel taken along line E-E′ of FIG. 32. As shown in FIG. 29,FIG. 32 and FIG. 33, the difference between the pixel structure 7 ofdisplay panel of the present embodiment and the first embodiment to thesixth embodiment mentioned above is that the first pixel electrode 12 issubstantially a full-surfaced electrode which completely covers thefirst alignment region 101, the second alignment region 102, the thirdalignment region 103 and the fourth alignment region 104 without anyslits or openings. In addition, the insulation layer of the presentinvention is a patterned insulation layer 15 as shown in FIG. 30, FIG.32 and FIG. 33, not a full-surfaced insulation layer. The patternedinsulation layer 15 is disposed on the first substrate 10 and partiallycovers the first pixel electrode 12, wherein the patterned insulationlayer 15 includes a plurality of insulation branch patterns. Theinsulation branch patterns includes a plurality of first insulationbranch patterns 151, a plurality of second insulation branch patterns152, a plurality of third insulation branch patterns 153 and a pluralityof fourth insulation branch patterns 154. The first insulation branchpatterns 151 are disposed in the first alignment region 101 and at leasta portion of the first branch patterns 151 substantially extends along afirst direction D1. The second insulation branch patterns 152 aredisposed in the second alignment region 102 and at least a portion ofthe second branch patterns 152 substantially extends along a seconddirection D2. The third insulation branch patterns 153 are disposed inthe third alignment region 103 and at least a portion of the thirdbranch patterns 153 substantially extends along a third direction D3.The fourth insulation branch patterns 154 are disposed in the fourthalignment region 104 and at least a portion of the fourth branchpatterns 154 substantially extends along a fourth direction D4. Thefirst direction D1, the second direction D2, the third direction D3 andthe fourth direction D4 are different to one another. In addition, aslit 15S is disposed between any two adjacent insulation branchpatterns. The second pixel electrode 16 of the present embodiment may bethe same as the second pixel electrode 16 of the embodiments mentionedabove, for example, the second pixel electrode 16 substantially includesa cruciform electrode, but not limited thereto. Furthermore, thepatterned insulation layer 15 of the present embodiment may furtherinclude an insulation main part 15M disposed in a portion of the firstalignment region 101, a portion of the second alignment region 102, aportion of the third alignment region 103, a portion of the fourthalignment region 104 and a common boundary of any two adjoiningalignment regions of the alignment regions. The insulation main part 15Mis connected to an end 151A of each of the first branch patterns 151, anend 152A of each of the second branch patterns 152, an end 153A of eachof the third branch patterns 153 and an end 154A of each of the fourthbranch patterns 154. The second pixel electrode 16 substantiallyoverlaps the insulation main body 15M of the patterned insulation layer15 in the vertical projection direction Z. For instance, the insulationmain body 15M of the patterned insulation layer 15 has a quadrangleinsulation pattern, the quadrangle insulation pattern has a first sideedge Z1, a second side edge Z2, a third side edge Z3 and a fourth sideedge Z4. The first side edge Z1 is disposed in the first alignmentregion 101 and is connected to the first insulation branch patterns 151.The second side edge Z2 is disposed in the second alignment region 102and is connected to the second insulation branch patterns 152. The thirdside edge Z3 is disposed in the third alignment region 103 and isconnected to the third insulation branch patterns 153. The fourth sideedge Z4 is disposed in the fourth alignment region 104 and is connectedto the fourth insulation branch patterns 154. The first side edge Z1,the second side edge Z2, the third side edge Z3 and the fourth side edgeZ4 may be but not limited to be perpendicular to the first direction D1,the second direction D2, the third direction D3 and the fourth directionD4, respectively. In addition, the first alignment film 18 is disposedon the first substrate 10 and covers the second pixel electrode 16, thepatterned insulation layer 15 and the first pixel electrodes 12. Thesecond alignment film 24 is disposed on the second substrate 20 andcovers the common electrode 22.

The driving method of the pixel structure of display panel according tothe second to the seventh embodiment of the present invention is thesame as the driving method of the pixel structure of display panelaccording to the first embodiment and will not be redundantly described.

Please refer to FIGS. 34-35. FIG. 34 is a top view schematicallyillustrating a pixel structure of display panel according to an eighthembodiment of the present invention. FIG. 35 is a cross-sectional viewof the pixel structure of display panel taken along line G-G′ of FIG.34. As shown in FIGS. 34-35, the pixel structure 8 of display panelaccording to the present embodiment is similar to the pixel structure 7of display panel according to the seventh embodiment. The differencebetween the present embodiment and the seventh embodiment is that thepixel structure 8 of display panel of the present embodiment does notinclude a second pixel electrode. Without the second pixel electrode,the first alignment film 18 is disposed on the first substrate 10 andcovers the patterned insulation layer 15 and the first pixel electrodes12. The second alignment film 24 is disposed on the second substrate 20and covers the common electrode 22. The pixel structure 8 of displaypanel is able to reduce the width of the dark line in the proximity ofthe slits 15S in the first alignment region 101, the second alignmentregion 102, the third alignment region 103 and the fourth alignmentregion 104, and thus increase the transmittance.

In conclusion, an insulation layer is disposed between the first pixelelectrode and the liquid crystal layer in the pixel structure of displaypanel of the present invention so as to reduce the electric fielddistortions due to the fringe field effect of the edge of the main partof the first pixel electrode and the edge of the branch electrodes. Bysubstituting the fringe field with the equipotential surface variationsprovided by the second pixel electrode, the irregular arrangement of theliquid crystal molecules can be eliminated, the generation of dark linesis avoided and therefore the transmittance is increased

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A pixel structure of display panel, comprising: afirst substrate, the first substrate having a plurality of alignmentregions, the alignment regions comprising a first alignment region, asecond alignment region, a third alignment region and a fourth alignmentregion; a second substrate, disposed opposite to the first substrate; aliquid crystal layer, comprising a plurality of liquid crystal moleculesdisposed between the first substrate and the second substrate, whereinthe liquid crystal molecules located at the first alignment region, thesecond alignment region, the third alignment region and the fourthalignment region have different alignment directions; a first pixelelectrode, disposed on the first substrate, wherein the first pixelelectrode is a patterned electrode and the first pixel electrodecomprises: a plurality of first branch electrodes, disposed in the firstalignment region, wherein at least a portion of the first branchelectrodes is substantially arranged along a first direction; aplurality of second branch electrodes, disposed in the second alignmentregion, wherein at least a portion of the second branch electrodes issubstantially arranged along a second direction; a plurality of thirdbranch electrodes, disposed in the third alignment region, wherein atleast a portion of the third branch electrodes is substantially arrangedalong a third direction; a plurality of fourth branch electrodes,disposed in the fourth alignment region, wherein at least a portion ofthe fourth branch electrodes is substantially arranged along a fourthdirection, the first direction, the second direction, the thirddirection and the fourth direction are different to one another, and thefirst branch electrodes, the second branch electrodes, the third branchelectrodes and the fourth branch electrodes are electrically connectedto one another; and a main part, disposed in a common boundary of anytwo adjoining alignment regions of the alignment regions, wherein themain part is electrically connected to a first end of each of the firstbranch electrodes, a first end of each of the second branch electrodes,a first end of each of the third branch electrodes and a first end ofeach of the fourth branch electrodes; an insulation layer, disposed onthe first substrate and covering the first pixel electrode; a secondpixel electrode, disposed on the insulation layer, wherein the secondpixel electrode is a patterned electrode and the second pixel electrodeis disposed over the common boundary of any two adjoining alignmentregions of the alignment regions; and a common electrode, disposed onthe second substrate, wherein the main part of the first pixel electrodesubstantially overlaps the second pixel electrode in a verticalprojection direction.
 2. The pixel structure of display panel of claim1, wherein the first pixel electrode further comprises an outer framepart surrounding the first alignment region, the second alignmentregion, the third alignment region and the fourth alignment region, andthe outer frame part is connected to the first branch electrodes, thesecond branch electrodes, the third branch electrodes and the fourthbranch electrodes.
 3. The pixel structure of display panel of claim 2,wherein the outer frame part is connected to a second end of each of thefirst branch electrodes, a second end of each of the second branchelectrodes, a second end of each of the third branch electrodes and asecond end of each of the fourth branch electrodes.
 4. The pixelstructure of display panel of claim 3, wherein the second pixelelectrode surrounds the first alignment region, the second alignmentregion, the third alignment region and the fourth alignment region, andthe outer frame part of the first pixel electrode substantially overlapsthe second pixel electrode in the vertical projection direction.
 5. Thepixel structure of display panel of claim 4, wherein the main part ofthe first pixel electrode has an opening corresponding to the commonboundary of any two adjoining alignment regions of the alignmentregions, and the opening of the main part of the first pixel electrodeat least partially overlaps the second pixel electrode in the verticalprojection direction.
 6. The pixel structure of display panel of claim2, wherein the main part of the first pixel electrode is furtherdisposed in a portion of the first alignment region, a portion of thesecond alignment region, a portion of the third alignment region, and aportion of the fourth alignment region, and the outer frame part isconnected to a second end of each of the first branch electrodes, asecond end of each of the second branch electrodes, a second end of eachof the third branch electrodes and a second end of each of the fourthbranch electrodes.
 7. The pixel structure of display panel of claim 6,wherein the main part of the first pixel electrode comprises aquadrangle electrode, the quadrangle electrode has a first side edge, asecond side edge, a third side edge and a fourth side edge, the firstside edge is disposed in the first alignment region and is connected tothe first branch electrodes, the second side edge is disposed in thesecond alignment region and is connected to the second branchelectrodes, the third side edge is disposed in the third alignmentregion and is connected to the third branch electrodes, the fourth sideedge is disposed in the fourth alignment region and is connected to thefourth branch electrodes, and the second pixel electrode comprises acruciform electrode.
 8. The pixel structure of display panel of claim 7,wherein the main part of the first pixel electrode has an openingcorresponding to the common boundary of any two adjoining alignmentregions of the alignment regions, and the opening of the main part ofthe first pixel electrode at least partially overlaps the second pixelelectrode in the vertical projection direction.
 9. The pixel structureof display panel of claim 1, wherein the first pixel electrode iselectrically connected to the second pixel electrode.
 10. The pixelstructure of display panel of claim 1, wherein the first pixel electrodeis not connected to the second pixel electrode, the first pixelelectrode has a first driving voltage, and the second pixel electrodehas a second driving voltage, wherein the second driving voltage ishigher than the first driving voltage.
 11. The pixel structure ofdisplay panel of claim 1, further comprising: a first alignment film,disposed on the first substrate and covering the insulation layer andthe second pixel electrode, wherein the first alignment film has a firstpolymer auxiliary alignment layer; and a second alignment film, disposedon the second substrate and covering the common electrode, wherein thesecond alignment film has a second polymer auxiliary alignment layer.12. A pixel structure of display panel, comprising: a first substrate,the first substrate having a plurality of alignment regions, thealignment regions comprising a first alignment region, a secondalignment region, a third alignment region and a fourth alignmentregion; a second substrate, disposed opposite to the first substrate; aliquid crystal layer, comprising a plurality of liquid crystal moleculesdisposed between the first substrate and the second substrate, whereinthe liquid crystal molecules located at the first alignment region, thesecond alignment region, the third alignment region and the fourthalignment region have different alignment directions; a first pixelelectrode, disposed on the first substrate, wherein the first pixelelectrode is a patterned electrode and the first pixel electrodecomprises: a plurality of first branch electrodes, disposed in the firstalignment region, wherein at least a portion of the first branchelectrodes is substantially arranged along a first direction; aplurality of second branch electrodes, disposed in the second alignmentregion, wherein at least a portion of the second branch electrodes issubstantially arranged along a second direction; a plurality of thirdbranch electrodes, disposed in the third alignment region, wherein atleast a portion of the third branch electrodes is substantially arrangedalong a third direction; and a plurality of fourth branch electrodes,disposed in the fourth alignment region, wherein at least a portion ofthe fourth branch electrodes is substantially arranged along a fourthdirection, the first direction, the second direction, the thirddirection and the fourth direction are different to one another, and thefirst branch electrodes, the second branch electrodes, the third branchelectrodes and the fourth branch electrodes are electrically connectedto one another; an insulation layer, disposed on the first substrate andcovering the first pixel electrode; a second pixel electrode, disposedon the insulation layer, wherein the second pixel electrode is apatterned electrode and the second pixel electrode is disposed over atleast one boundary of each of the alignment regions; and a commonelectrode, disposed on the second substrate; wherein a first end of aportion of the first branch electrodes is connected to a first end of aportion of the second branch electrodes, a first end of the otherportion of the first branch electrodes is connected to a first end of aportion of the fourth branch electrodes, a first end of a portion of thethird branch electrodes is connected to a first end of the other portionof the second branch electrodes, a first end of the other portion of thethird branch electrodes is connected to a first end of the other portionof the fourth branch electrodes, and the second pixel electrodesubstantially overlaps the first ends of the first branch electrodes,the first ends of the second branch electrodes, the first ends of thethird branch electrodes and the first ends of the fourth branchelectrodes in a vertical projection direction.
 13. A pixel structure ofdisplay panel, comprising: a first substrate, the first substrate havinga plurality of alignment regions, the alignment regions comprising afirst alignment region, a second alignment region, a third alignmentregion and a fourth alignment region; a second substrate, disposedopposite to the first substrate; a liquid crystal layer, comprising aplurality of liquid crystal molecules disposed between the firstsubstrate and the second substrate, wherein the liquid crystal moleculeslocated at the first alignment region, the second alignment region, thethird alignment region and the fourth alignment region have differentalignment directions; a first pixel electrode, disposed on the firstsubstrate, wherein the first pixel electrode is a patterned electrodeand the first pixel electrode comprises: a plurality of first branchelectrodes, disposed in the first alignment region, wherein at least aportion of the first branch electrodes is substantially arranged along afirst direction; a plurality of second branch electrodes, disposed inthe second alignment region, wherein at least a portion of the secondbranch electrodes is substantially arranged along a second direction; aplurality of third branch electrodes, disposed in the third alignmentregion, wherein at least a portion of the third branch electrodes issubstantially arranged along a third direction; a plurality of fourthbranch electrodes, disposed in the fourth alignment region, wherein atleast a portion of the fourth branch electrodes is substantiallyarranged along a fourth direction, the first direction, the seconddirection, the third direction and the fourth direction are different toone another, and the first branch electrodes, the second branchelectrodes, the third branch electrodes and the fourth branch electrodesare electrically connected to one another; an outer frame part,surrounding the first alignment region, the second alignment region, thethird alignment region and the fourth alignment region, wherein theouter frame part is electrically connected to the first branchelectrodes, the second branch electrodes, the third branch electrodesand the fourth branch electrodes; and a main part, disposed in a commonboundary of any two adjoining alignment regions of the alignmentregions, wherein the main part is electrically connected to two ends ofa portion of the first branch electrodes, two ends of a portion of thesecond branch electrodes, two ends of a portion of the third branchelectrodes and two ends of a portion of the fourth branch electrodes,the outer frame part is connected to two ends of the other portion ofthe first branch electrodes, two ends of the other portion of the secondbranch electrodes, two ends of the other portion of the third branchelectrodes and two ends of the other portion of the fourth branchelectrodes; an insulation layer, disposed on the first substrate andcovering the first pixel electrode; a second pixel electrode, disposedover the insulation layer, wherein the second pixel electrode is apatterned electrode and the second pixel electrode is disposed over anoutside boundary of the first alignment region, an outside boundary ofthe second alignment region, an outside boundary of the third alignmentregion, an outside boundary of the fourth alignment region, a commonboundary of the first alignment region and the fourth alignment regionand a common boundary of the second alignment region and the thirdalignment region; and a common electrode, disposed on the secondsubstrate, wherein the second pixel electrode partially overlaps themain part of the first pixel electrode in a vertical projectiondirection.
 14. The pixel structure of display panel of claim 13, whereinthe main part of the first pixel electrode has an opening correspondingto the common boundary of any two adjoining alignment regions of thealignment regions, and the opening of the main part of the first pixelelectrode at least partially overlaps the second pixel electrode in thevertical projection direction.